To improve the 4H-SiC/SiO

2

interface quality phosphorous-doped technology and nitrogen-annealed technology were introduced.The phosphorous atoms were introduced into the 4H-SiC/SiO

2

interface by thermal annealing with a planar diffusion source (PDS).Current-voltage test was used to characterize the interface quality.To obtain the interface state density (

D

it

) lying energetically within 0.2eV-0.4eV of the conduction band edge (

E

c

)

the C-V data was analyzed by using Terman method.It is apparent that the phosphorous-doped technology can reduce the interface state density near the conduction band of 4H-SiC effectively and increase the channel mobility and decrease the on resistanc

e.Compared with NO passivated devices

P-doped devices have better performance.What's more

this technology has been applied to fabricate 1.2kV 4H-SiC DMOSFET firstly.Fabricated devices show a significant improvement with an on resistance of 20m

drain-source current of 75A

threshold voltage of 2.4V.